Vanguard range of telephones comprises:-
- Tele 4001 AR, Vanguard (basic - Pictured).
- Tele 4002 AR, Vanguard 10 address.
- Tele 4003 AR, Vanguard IC (basic with inductive coupler).
(Teles 4001 & 4003 are now available with Vanguard II circuitry).
'Customised' Vanguards (i.e. with customer's logo printed on the case) were are also
The Vanguard Telephone range is designed specifically for the rental market, all models
are similar in appearance and offer the following facilities:-
- LD, Mixed or MF (TouchTone) Signalling (user switchable).
- Earth-loop or Timed-break recall (user switchable).
- 24 digit last number redial memory.
- Secrecy (non-locking microphone cut-off facility).
- Tone caller (with High, Low, off control).
- For table or wall mounted use.
- Inductive coupler receiver Inset (Vanguard IC models only).
- 10 Address Memory (each address can store up to 18 digits including * and # but not
recall) (Vanguard 10 models only).
A three position slider switch (labelled LD-MFT-MFE) is provided on the right hand side of
the instrument. This is normally supplied set to LD to offer Loop Disconnect/Mixed
signalling with Earth recall but should be shifted to 'MFE' for MF signalling with Earth
recall or 'MFT' for MF signalling with Timed Break recall (TouchTone) as necessary.
Mixed signalling is the facility whereby a call may be set up in the LD mode and continued
for the duration of the call in the MF mode by pressing the '*' button.
Numbers are stored on Vanguard 10 by the following method:- lift handset, press 'P', press
required memory button, key number to be stored, press 'P'. Where numbers greater than 18
digits need to be stored, the remaining digits may be stored under other memory button(s)
or keyed manually.
There is no provision for storing PBX access pauses in any of the memory stores, PBX
access codes may be keyed manually before using stored number or last number redial
The Inductive Coupler (IC) versions are compatible with behind-the-ear hearing aids when
these are switched to the 'T' position (normally the Polar White model).
Made by NTE (earlier models by BTCE)
Approved under Approval numbers S/1000/3/J/501151 (Vanguard) and S/1000/3/J/501080
(Vanguard 10) for use on DELs and PBXs in categories 1,3,5,7,9 & 11.
Vanguard and Vanguard 10 have a REN of 1 and are intended for use in normal Domestic or
They are not suited for use in bathrooms or other locations prone to damp or condensation.
Approximate overall dimensions are 216mm x 152mm x 70mm, weight 847 grams. When mounted in
an enclosure (e.g. in a lift telephone housing) an additional 13mm should be allowed along
one edge for the handset cord. NB only Vanguard II Inductive Coupler models should be used
for telephones in lifts.
Two 2.5mm x 30mm pan-head wood screws and wall plugs (requiring 5/16" hole) are
provided for wall mounted use via key-hole slots in the base of the instrument.
The Signalling switch should be set on installation according to the type of exchange/PBX
it is used on, i.e.:-
MFT for Digital or Modernised TXE4 exchanges and a-minority of PBXs (i.e. for TouchTone,
Star Services and Timed Break Recall PBXs).
MFE for the majority of modern PBXs (i.e. with MF signalling with Earth recall).
LD for unmodernised exchanges and older PBXS.
Table mounted - the rear legs should be extended to ensure handset fully operates the
gravity switch on clear down.
Wall mounted - the handset and line cords may be routed through the alternative channels
in the base as required and the line cord may be shortened. The handset retaining lug
should be turned through 180 degrees to support the handset.
BT's warranty from the manufacturer is for 24 months from date marking on the base (Week
& Year forming first four digits of the serial number), items failing within warranty
should be returned with fault details attached to District stores for warranty handling.
BT Item Codes
Telephone 4001 AR Vanguard, Polar White
Telephone 4001 AR Vanguard, Light Beige
Telephone 4001 AR Vanguard, Charcoal Grey
Telephone 4003 AR Vanguard, Red - June 1992
Telephone 4003 AR Vanguard 10, Alpine White - June 1992
Telephone 4003 AR Vanguard 10, Oatmeal - June 1992
Telephone 4002 AR Vanguard 10, Polar White - 1992
Telephone 4002 AR Vanguard 10, Light Beige - 1992
Telephone 4002 AR Vanguard 10, Charcoal Grey - 1992
Telephone 4003 AR Vanguard IC, Polar White - 1992
Telephone 4003 AR Vanguard 10, Red
Idle - Normal capacitor loop, additionally these telephones draw on-hook current
(typically 10 micro Amps) to maintain stored/last number memory. This may give apparent
'Low Loop' line test conditions.
Seized - Normal press button telephone loop. The electronic keypad and transmission
circuitry may give 'high resistance' tele loop line test conditions as with other press
There is no provision for memory back-up batteries in Vanguard or Vanguard 10 telephones,
stored/last number memory cannot be guaranteed if the telephone is removed from line for
more than 5 minutes although in practice memory may last for several hours on these
- Original Vanguard (basic) and Vanguard 10, fixed duration tone bursts of approximately
- Vanguard II, continuous tone whilst button is pressed.
Timed break recall
- All models, approximately 90 ms
- All models, continuous whilst recall button is pressed (to a maximum of 1 second).
Vanguard & Vanguard 10 have good immunity against RFI from 100kHz to 200MHz.
Identified interworking problems
Original Vanguard basic and Vanguard 10 (i.e. Vanguards with processor 'watch dog'
- Delayed dial tone (approx. 0.5 second delay on initial power up)
- No dial tone when used on low voltage switching systems such as 'Consort' (i.e. where
line Voltage can be lets than 20 Volts)
- No dial tone on low voltage exchange line systems such as 'Local Line Concentrator
- Call drop-out or wrong numbers when used with Autodials 402 (e.g. for telephones in
- Calls lost in transfer when used on Renown on Digital exchange lines (call goes into
hold at main exchange).
- Last number redial lost when used on Renown (memory clears when recall button is pressed
to access line).
- Last number redial incorrect, when recall button is held between 0.2 and 1 second. The
'L' memory stores dialled digits after 'recall' operation instead of digits dialled prior
- Last number redial non-op when user flashes hook switch quickly. This results in
exchange recognising the line break (and giving dial tone), but the break is too short for
telephone to recognise.
Most of the above problems (a-d) have been overcome on Vanguard (basic) II models,
these may be identified by:
Serial Numbering (Serial Number 9044xxxx onwards).
MF signalling (Vanguard II are not fixed burst signalling).
Recall switch (Vanguard II has a 'soft button' instead of a mechanical recall switch).
Problems (e-g) are due to be resolved on later Vanguard II models.
Vanguard II telephones have an 'electronic' earth recall circuitry which relies on the
telephone being powered up to function correctly and hence are not suitable for use as
'earth calling' PBX power fail extensions.
Vanguard II telephones with continuous tone signalling are not recommended for use on the
Pentara. When an access digit e.g. 9 (for exchange line) is keyed, the Pentara can provide
the exchange line before the key is released, causing a further 9 to be extended to the
This is a Pentara comparability problem which, in the light of the Pentara's age, is
unlikely to be solved.
It would be prudent to resist installing any Vanguard telephones on the Pentara System as
swop out to a non-continuous pulse version will be impossible in the future.